Electric toothbrush

ABSTRACT

An electric toothbrush including a pressure fluid device for applying fluid under pressure to teeth to be cleaned or to a bristle set. The pressure fluid device includes a pressure fluid supply in the interior of a movable drive translator. A brush part with a carrier tube is movably mounted with a drive translator therein adapted to be coupled to a drive element in a handle part. A movably mounted bristle carrier mounts a set of bristles and is adapted to be driven in an oscillatory manner by the drive translator. A motor in the handle part drives a drive element adapted to be coupled to a drive element in the brush part and with a pressure fluid conveying device driven by the motor. A pressure fluid channel, which directs the pressure fluid to the toothbrush head, is integrated into the drive translator.

The present invention relates to electric toothbrushes, and moreparticularly, to electric toothbrushes that deliver fluid under pressureto teeth to be cleaned or to a bristle set.

BACKGROUND

Toothbrushes have been proposed in which pressurized-air nozzles areprovided adjacent to the bristles in order to cleanse teeth andinterproximal spaces with pressurized air. In addition to the cleaningaction of the bristles, the pressurized air blows away adheringparticles and produces a massage effect. U.S. Pat. No. 3,823,710discloses a handheld toothbrush in which a pulsed stream of air isdischarged from a tip element arranged at the forward end adjacent tothe bristle set, said stream of air being produced by a tandem diaphragmpump. The tip element is connected with a pressurized air channel in theneck of the toothbrush which is connected to the air pump at the handlepart through a tube. U.S. Pat. No. 3,178,754 proposes an electrictoothbrush with a compressed-air device. Provided in the handle part ofthe toothbrush is an air pump which directs compressed air into theinterior of the moving toothbrush head. Formed underneath the bristlecarrier is a pressure fluid chamber in which the pulsing air pressurearriving from the piston pump develops into a uniform stream, exiting tothe bristle set through outlet nozzles as a substantially uniform flowof air.

Patent DE 20 19 003 A1 discloses an electric toothbrush where the brushhead impinges a jet of water on the teeth to be cleaned or thesurrounding gums. The water jet device comprises a compressor driven bythe drive motor of the toothbrush and conveying pressurized air into awater reservoir in the handle of the toothbrush, thereby providing apressurized water-and-air mixture. This mixture is directed through aline into a feed channel in the interior of the brush attachment fromwhich it is fed to the brush head. In contrast to modern brushattachments, this known brush attachment is moved overall, that is, ithas no brush tube which is adapted to be fixedly coupled to the handleand would have in its interior a separate drive train and at its forwardend a movably mounted bristle carrier.

SUMMARY

The aforementioned problems are overcome by the present disclosure of anelectric toothbrush including a brush part having a pressure fluiddevice for applying fluid under pressure to the teeth to be cleaned orto the bristle set. The pressure fluid device comprises a pressure fluidsupply in the interior of the movable drive translator. A pressure fluidchannel, which directs the pressure fluid to the toothbrush head, ishence integrated into the typically rod- or bar-shaped drive translator.

In a preferred embodiment, the drive translator is constructed as ahollow shaft mounted in the carrier tube for rotation about itslongitudinal axis having a coupling member at an end close to the handlepart for coupling a drive element of the handle portion. The couplingmember comprises a fluid coupling through which the fluid channel in theinterior of the hollow shaft is connectible with a fluid channel in theinterior of the drive shaft element of the handle part. The oscillatoryrotary drive movement of the drive shaft in the carrier tube may beconverted into the drive movement of the bristle carrier in a variety ofways. In one embodiment, an eccentric coupling member is fastened to thedrive shaft in a manner preventing relative rotation, where theeccentric coupling member is engaged with the bristle carrier in orderto drive the latter in a rotary oscillatory manner. The motion axis ofthe bristle carrier and the motion axis of the drive shaft extend indirections essentially normal to each other.

In yet another embodiment, the driving motion of the drive translator inthe carrier tube is along a single axis only, thereby facilitating thepassing-on of the fluid stream which exits from the end of the drivetranslator close to the brush head. The fluid stream is introduced intoa fluid channel in the carrier tube wall in the area of the bearingcarrying the drive translator for rotation about its longitudinal axis.Hence, the fluid line in the carrier tube wall is in fluid communicationwith the bearing section for the drive translator. With its other end,the pressure fluid channel in the carrier tube wall is in fluidcommunication with the movably mounted bristle carrier. To simplify theintroduction of the pressure fluid from the pressure fluid channel inthe carrier tube wall into the bristle carrier, the pressure fluidchannel is routed from the carrier tube wall into the bearing section inwhich the bristle carrier is rotatably mounted. In a preferredembodiment, the bristle carrier may sit on a bearing pin secured in ahead section of the brush carrier tube. The fluid channel passespreferably through the bearing pin of the bristle carrier. A hollowpivot pin for the bristle carrier is provided, through which thepressure fluid can be supplied to the bristle carrier. Extending throughthe interior of the bristle carrier is then likewise at least onepressure fluid channel which is routed to a pressure fluid outletorifice at the base of the bristle carrier in which the bristles areanchored. Conveniently, the bristle carrier provides a central dischargenozzle which is constructed such that a pressure fluid jet is dischargedfrom the bristle carrier roughly parallel to the bristle main directionand directed against the teeth to be cleaned.

The pressure fluid supply in the interior of the brush part, in apreferred embodiment, dispenses with separate flexible tubes and isformed exclusively in the interior of functional components of the brushpart that already exist for the performance of other functions. Thepressure fluid channels run in components as, for example, the movabledrive train in the interior of the carrier tube, all of whichaccordingly fulfill a dual function. Because separate flexible tubes andthe like are dispensed with, a highly compact construction of the brushpart can be accomplished.

The handle part of the electric toothbrush, in a preferred embodiment,has a compact structure. The pressure fluid conveying device is seatedbetween the motor and the gear step and is driven, together with thegear step, by a common drive element. Hence, no separate gear step forthe pressure fluid conveying device is provided. The pressure fluidconveying device transmits the drive motion of the motor to the gearstep which generates the movement of the drive translator in theinterior of the carrier tube of the brush section, meaning that thedrive motion of the motor is transmitted through the pressure fluidconveying device to the gear step. Additional losses, which would beproduced by a further gear step, are avoided. Furthermore, comparativelyshort pressure fluid lines can find application, which in the knownarrangement of the pressure fluid conveying device on the motor sideremote from the brush part are substantially longer.

The compact arrangement is, however, not at the expense of the pressurefluid conveying device being integrated into the housing of the handlepart or being formed integrally by parts of the drive train. In afurther embodiment, the pressure fluid conveying device is a separateassembly in its own right, which is arranged in the interior of thehandle part. Preferably, the pressure fluid conveying device is an airpump, in which the pressure fluid discharge is preferably only air, thatis, no water is added and no water jet is discharged. The pressure fluidchannels form air channels.

In yet another embodiment, the pressure fluid conveying device is seatedon an eccentric element connected to the motor shaft and carries acoaxial eccentric element for driving the gear step. Accordingly, thepressure fluid conveying device may sit on the same eccentric elementthat drives the gear step which generates the drive motion for the drivetranslator in the carrier tube of the brush part.

The drive element extending out of the housing of the handle part anddriven in an oscillatory manner is utilized, in a preferred embodiment,for passing on the pressure fluid stream generated by the pump, wherethe drive element is adapted to be coupled to the drive translator inthe carrier tube of the brush part. The drive element, drivable inoscillatory manner in the handle part, may have in its interior apressure fluid channel which communicates with the pressure fluidconveying device. Preferably, the drive element is constructed as arotatably mounted hollow shaft having at its end protruding from thehandle part a coupling member for coupling to the drive translator inthe brush part, with the coupling member comprising a fluid couplingallowing the pressure fluid to be directed into the interior of thedrive translator in the brush part.

In an embodiment where the construction of the two drive elementsincludes coupled hollow shafts and the pressure fluid passes directlyfrom oscillatory drive element to oscillatory drive element, it ispossible to construct the coupling of the carrier tube of the brush partto the handle part in a simple manner. The connector on the handle parthousing can be free from a pressure fluid coupling for releasablyfastening the carrier tube of a brush part. Both the drive coupling andthe pressure fluid coupling are provided on the movable drive elementsprovided in the interior of the brush tube and typically fabricated frommetal.

The hollow shaft mounted in the handle part and driven by the gear stepmay be connected to the pressure fluid conveying device in a variety ofways. To compensate for the movement of the drive element driven tooscillate and protruding from the handle part housing, the connectionmay be implemented in the form of a flexible tube connectible to thepressure outlet of the pressure fluid conveying device at its one endand to the drive element moved in an oscillatory pattern at its otherend. In a preferred embodiment, provision can be made for the flexibletube to be connected to a connecting rod which drives the hollow shaftin the handle part and has in its interior a pressure fluid channelcommunicating with the pressure fluid channel in the interior of thehollow shaft. Preferably, the pressure conveying device constructed as apump is arranged such that its pressure outlet lies at the end facingthe brush head. This makes it possible to provide a short length offlexible tubing.

Further objects, advantages, features and application possibilities ofthe present invention will become apparent from the subsequentdescription of a preferred embodiment with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electric toothbrush having a handlepart and, seated thereon, a brush part with a bristle carrier adapted tobe driven in rotary oscillatory manner in accordance with a preferredembodiment of the invention;

FIG. 2 is a perspective view of the interior of the handle part, withthe handle part housing cut away to expose the arrangement of a pressurefluid pump and the gear step for generating the drive motion;

FIG. 3 is a perspective sectional view of the brush part of FIG. 1,showing the path of the pressure fluid supply to the driven bristlecarrier through the drive train;

FIG. 4 is a schematic sectional view of the pump provided in the handlepart and its connection to a pressure fluid channel in the interior of adrive element driven to oscillate in the handle part, which driveelement is coupled to a drive translator in the brush part; and

FIG. 5 is a schematic part sectional view of the coupling between thepump and the eccentric element of the motor for driving the toothbrush.

DETAILED DESCRIPTION

The toothbrush shown in FIG. 1 comprises a handle part 1 with anessentially cylindrical handle part housing 2 and a brush part 3 with anessentially cylindrical carrier tube 4 mounting at its head section 5 abristle carrier 6 for rotation about an axis of rotation 21 transverseto the longitudinal direction of the toothbrush. The brush part 3 isreleasably connected to the handle part 1, so that the brush part 3 canbe replaced when worn.

Arranged in the interior of the handle part housing 2, which is omittedin FIGS. 2 and 4, is an electric motor 7 having a motor shaft 8 on whicha non-circular drive element 9 is seated in a manner preventing relativerotation. Seated on the non-circular drive element 9 is an air pump 10which is arranged in front of the electric motor 7 in axial directionand is driven by the drive element 9. The same drive element 9 or adrive element 9 coaxially connected therewith extends through the airpump 10, protruding therefrom with its forward end. Connected to theforward end of the drive element 9 is a gear step 11 in the form of afour-bar linkage, which transmits the drive motion of the drive element9 to a drive shaft 12 arranged parallel and in offset relation to themotor shaft 8. The gear step 11 is constructed such that the drive shaft12 is driven to oscillate in a rotary pattern about its longitudinalaxis. With its forward end the drive shaft 12 protrudes from the handlepart housing 2 which in the exit area of the drive shaft 12 isconstructed to fit around the drive shaft, forming a connector 13 forthe carrier tube 4 of the brush part 3.

The air pump 10 which is driven by the motor 7 via the drive element orthe eccentric element 9 has a pressure fluid outlet 14 at the end closeto the brush part 3, which outlet is connected to a pressure fluid line15 in the form of a flexible tube. The pressure fluid line 15 connectsthe pressure fluid outlet 14 of the air pump 10 with a pressure fluidchannel 16 formed in a connecting rod 17 that drives the drive shaft 12.The pressure fluid channel 16, which is constructed as a flexible tube,is sufficiently flexible to be able to compensate for the movement ofthe drive shaft 12. The pressure fluid channel 16 in the connecting rod17 is in fluid communication with a pressure fluid channel 18 in theinterior of the drive shaft 12 which is constructed as a hollow shaft.The pressure fluid channel 18 has its outlet at the free end of thedrive shaft that extends out of the handle part 1 where a couplingmember 19 or coupling section is provided for coupling the drive shaft12 to a drive translator in the interior of the carrier tube 4 of thebrush part 3.

As FIG. 5 shows, there is no rigid, that is, completely immovableconnection provided between the drive element 9 and the air pump 10.Rather, the connection is of such flexibility that an angular offsetbetween the drive element 9 and the air pump 10 or the connection of thegear step 11 can be compensated for. To this effect, the drive element 9is not completely straight but has in longitudinal direction slightlybarreled flanks which enable the air pump 10 to tilt somewhat in adirection transverse to the longitudinal axis to balance an angularoffset. The air pump 10 sits directly on the polygonal connector 13, theair pump has no bearing of its own at the motor end, any bearing beingformed directly by the drive element 9.

The brush part 3 is equipped with an approximately circular bristle set20 mounted on the disk- or plate-shaped bristle carrier 6. As FIG. 3shows, the bristle carrier 6 is mounted on the head section 5 of thecarrier tube 4 for rotation about an axis of rotation 21 essentiallynormal to the longitudinal axis of the toothbrush. The axis of rotation21 is defined by a bearing pin 22 received in a corresponding bore inthe head section 5 of the brush part 3. The bristle carrier 6 has acorresponding bore with which it sits on the bearing pin 22.

To transmit the drive motion of the drive shaft 12 in the handle part tothe bristle carrier 6, the carrier tube 4 mounts in its interior a drivetranslator 23 constructed as a drive shaft that is mounted for rotationabout its longitudinal axis. With its end close to the head section thedrive shaft sits in a bearing bore 24 formed in the body of the brushpart 3. With its end close to the handle part the drive shaft 23 can belocked with the drive shaft 12 of the handle part in a manner preventingrelative rotation. The two drive shafts 12 and 23 have complementarycoupling sections 19 and 25 engageable with each other in a non-rotatingrelationship. In this arrangement the coupling sections 25 also form afluid coupling to direct the air stream exiting from the drive shaft 12of the handle part into the interior of the drive shaft 23 which islikewise constructed as a hollow shaft. Hence the interior of the driveshaft 23 forms likewise a pressure fluid channel.

At its end close to the brush head the drive shaft 23 carriesnon-rotatably an eccentric element 26 receiving in it rotatably atranslator pin 27 that extends essentially parallel to the drive shaft23. With its forward end the translator pin 27 makes engagement with alongitudinal recess in the bristle carrier 6, which recess extendsparallel to the axis of rotation 21. Through the translator pin 27 theoscillatory rotational drive motion of the drive shaft 23 is convertedinto a likewise oscillatory rotational motion of the bristle carrier 6.

The pressure fluid channel in the interior of the drive shaft 23 has itsoutlet in the bearing section 28 around the bearing bore 24. The bearingsection 28 is formed by the material of the carrier tube 4 or the headsection 5 of the brush part 3. Adjoining in the wall of the head section5 is a pressure fluid channel 29 which communicates with the bearingsection 28 or the outlet of the pressure fluid channel in the driveshaft 23. The pressure fluid channel 29 opens into the bore for thebearing pin 22 which, constructed as a hollow pin, is formed ascontinuation of the pressure fluid channel 29. Extending through thebristle carrier 6, the pressure fluid channel finally ends on thesurface of the bristle carrier 6 in which the bristle set 20 isanchored. As FIG. 3 shows, the corresponding passage opening for thepressurized air extends approximately centrally all the way through thebristle carrier. The outlet orifice 30 is constructed as a nozzle sothat a high-velocity free jet exits between the bristles and impinges onthe teeth. Of course it would also be possible to provide a plurality ofoutlet orifices. In this event provision could be made in the bristlecarrier 6 for a distributor chamber which is supplied with pressurizedair from the channel in the rotary pin 21 and distributes it to pluraloutlet orifices. Preferable is however the previously described centraloutlet orifice.

To guarantee a sufficient level of hygiene, in one embodiment, thetoothbrush may be provided with an inlet-air filter in the base of thehandle part 1 so that only filtered air can be discharged.

1. A brush part for an electric toothbrush, the brush part comprising acarrier tube; a drive translator movably mounted within the carrier tubeand adapted to be coupled to a drive in an electric toothbrush handlepart; and a bristle carrier movably mounted to the carrier tube andcarrying a set of bristles, the bristle carrier adapted to be driven inan oscillatory manner by the drive translator; wherein the drivetranslator defines an interior fluid supply channel forming part of afluid path providing fluid communication to the bristle set.
 2. Thebrush part according to claim 1 wherein the drive translator isconstructed as a hollow shaft mounted in the carrier tube for rotationabout a longitudinal axis of the drive translator, and having at an endthereof a coupling member configured to couple the drive translator to adrive element of the handle part, said coupling member comprising afluid coupling through which the fluid channel of the drive translatoris connectible with a fluid channel in the interior of the drive elementof the handle part.
 3. The brush part according to claim 1 wherein thefluid supply channel of the drive translator provides fluidcommunication to a pressure fluid outlet orifice defined in the movablebristle carrier said orifice communicating with a pressure fluid supplychannel defined in a bearing pin of the bristle carrier.
 4. The brushpart according to claim 1 wherein the carrier tube defines a pressurefluid supply channel connecting the fluid supply channel of the drivetranslator with a pressure fluid channel defined in the bristle carrier.5. The brush part according to claim 1 wherein the pressure pathproviding fluid communication to the bristle carrier is free of flexibletubes and is formed exclusively in components of the brush part thatserve other functions in addition to providing hydraulic communication.6. A handle part of an electric toothbrush configured to drive aremovable brush part the handle part comprising: a handle part housing;a motor having a motor shaft, wherein the motor is located within thehandle part housing; a drive element operably connected to the motor andadapted to be coupled to a drive element in the brush part; a gear stepconfigured to couple the drive element to a drive element of the brushpart; a pressure fluid conveying device operably connected to the motor,wherein the pressure fluid conveying device defines a fluid outlet andis located between the motor and the gear step; and a common driveelement that drives the pressure fluid conveying device together withthe gear step.
 7. The handle part according to claim 6, the handle partfurther comprising a first eccentric element connected to the motorshaft, wherein the pressure fluid conveying device is seated on theeccentric element; and a second eccentric element located on thepressure fluid conveying device for driving the gear step.
 8. The handlepart according to claim 6 wherein the pressure fluid conveying device isan air pump.
 9. The handle part according to claim 6 wherein the driveelement defines a pressure fluid channel in fluid with the pressurefluid conveying device.
 10. The handle part according to claim 6 whereinthe drive element comprises a coupling member configured to couple to adrive element in the brush part.
 11. The handle part according to claim6 the handle part further comprising a flexible tube connecting thedrive element to the fluid outlet defined in the pressure fluidconveying device; and a connecting rod for driving the drive element,wherein the connecting rod is in fluid communication with the flexibletube.
 12. The handle part according to claim 6 wherein the pressurefluid conveying device comprises a pump casing separate from the handlepart housing.
 13. The handle part according to claim 6 wherein on thehandle part housing further comprises a connector for the releasablefastening of a carrier tube of the brush part, said connector being freefrom a drive coupling and free from a pressure fluid coupling. 14.(canceled)
 15. The brush part according to claim 3 wherein the pressurefluid outlet orifice defined in the movable bristle carrier is locatedin the bristle set.
 16. The brush part according to claim 1, the brushpart further comprising a pivot pin defining a hollow core, configuredto rotatably mount the bristle carrier on the carrier tube.
 17. Thebrush part according to claim 4 wherein the pressure fluid channeldefined in the bristle carrier has first and second ends, the first endterminating in a bearing section for carrying the drive translator andthe second end terminating in a bearing section for carrying the bristlecarrier.
 18. A replacement brush head configured to be received by anelectric toothbrush handle, the brush head comprising a carrier tube; adrive translator movable within the carrier tube and having a first endconfigured to be operably coupled to a drive of the electric toothbrushhandle; a bristle carrier movably mounted on the carrier tube andcarrying a set of bristles (20), the bristle carrier operably connectedto, and adapted to be driven in oscillatory manner by, the drivetranslator; wherein the drive translator defines a passage therein, thepassage forming a part of a fluid supply channel providing fluidcommunication between the first end of the drive translator and thebristle carrier, such that fluid pumped into the drive translator fromthe electric toothbrush handle is delivered to the bristle carrier. 19.The handle part of claim 6 wherein the motor drives the drive element inan oscillatory manner.
 20. The handle part of claim 6 wherein the gearstep comprises a four-bar linkage.
 21. The handle part of claim 9wherein the pressure fluid channel is defined in a rotatably mountedhollow shaft.
 22. The handle part of claim 10 wherein the couplingmember comprises a fluid coupling.